14
RESEARCH ARTICLE Open Access ReishiMax, mushroom based dietary supplement, inhibits adipocyte differentiation, stimulates glucose uptake and activates AMPK Anita Thyagarajan-Sahu 1 , Brandon Lane 1 and Daniel Sliva 1,2,3* Abstract Background: Obesity is a health hazard which is closely associated with various complications including insulin resistance, hypertension, dyslipidemia, atherosclerosis, type 2 diabetes and cancer. In spite of numerous preclinical and clinical interventions, the prevalence of obesity and its related disorders are on the rise demanding an urgent need for exploring novel therapeutic agents that can regulate adipogenesis. In the present study, we evaluated whether a dietary supplement ReishiMax (RM), containing triterpenes and polysaccharides extracted from medicinal mushroom Ganoderma lucidum, affects adipocyte differentiation and glucose uptake in 3T3-L1 cells. Methods: 3T3-L1 pre-adipocytes were differentiated into adipocytes and treated with RM (0-300 μg/ml). Adipocyte differentiation/lipid uptake was evaluated by oil red O staining and triglyceride and glycerol concentrations were determined. Gene expression was evaluated by semi-quantitative RT-PCR and Western blot analysis. Glucose uptake was determined with [ 3 H]-glucose. Results: RM inhibited adipocyte differentiation through the suppresion of expression of adipogenic transcription factors peroxisome proliferator-activated receptor-g (PPAR-g), sterol regulatory element binding element protein-1c (SREBP-1c) and CCAAT/enhancer binding protein-a (C/EBP-a). RM also suppressed expression of enzymes and proteins responsible for lipid synthesis, transport and storage: fatty acid synthase (FAS), acyl-CoA synthetase-1 (ACS1), fatty acid binding protein-4 (FABP4), fatty acid transport protein-1 (FATP1) and perilipin. RM induced AMP- activated protein kinase (AMPK) and increased glucose uptake by adipocytes. Conclusion: Our study suggests that RM can control adipocyte differentiation and glucose uptake. The health benefits of ReishiMax warrant further clinical studies. Background Obesity is increasing at an alarming rate in the devel- oped as well as developing countries [1]. In the United States obesity is increasing not only in adults but also in children [2]. Among various factors which contribute to the likelihood of death, obesity has escalated the chances of death by 20% and it has lately surpassed smoking as the number one cause of death in the US [3,4]. Accord- ing to survey carried out in 2007-2008 by the National Health and Nutrition Examination Survey (NHANES) nearly 32.2% of adult men and 35.5% of adult women were obese [5]. There are numerous epidemiological studies indicating that obese humans are at elevated risk of developing non-insulin-dependent (type 2) diabetes mellitus, hypertension, cancer and atherosclerosis [3,6,7]. There are several lines of evidence to show that obe- sity triggers the dysregulation of the endocrine function of the adipose tissue [8,9]. This suggests that adipose tissue is no longer considered to be an inert tissue solely responsible for energy store, instead is recognized as a major secretory organ, releasing a variety of adipocyto- kines such as adiponectin, leptin, resitin and visfatin [10]. These adipocytokines provide the link between obesity, insulin resistance and inflammatory disorders [10,11]. Differentiation of fibroblasts into adipose tissue requires chronological changes in the expression of numerous genes [12-14]. The initial events are orche- strated by several transcription factors, CCAAT/ * Correspondence: [email protected] 1 Cancer Research Laboratory, Methodist Research Institute, Indiana University Health, 1800 N Capitol Ave, E504, Indianapolis, IN 46202, USA Full list of author information is available at the end of the article Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74 http://www.biomedcentral.com/1472-6882/11/74 © 2011 Thyagarajan-Sahu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

RESEARCH ARTICLE Open Access ReishiMax, mushroom based

  • Upload
    others

  • View
    1

  • Download
    0

Embed Size (px)

Citation preview

Page 1: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

RESEARCH ARTICLE Open Access

ReishiMax, mushroom based dietary supplement,inhibits adipocyte differentiation, stimulatesglucose uptake and activates AMPKAnita Thyagarajan-Sahu1, Brandon Lane1 and Daniel Sliva1,2,3*

Abstract

Background: Obesity is a health hazard which is closely associated with various complications including insulinresistance, hypertension, dyslipidemia, atherosclerosis, type 2 diabetes and cancer. In spite of numerous preclinicaland clinical interventions, the prevalence of obesity and its related disorders are on the rise demanding an urgentneed for exploring novel therapeutic agents that can regulate adipogenesis. In the present study, we evaluatedwhether a dietary supplement ReishiMax (RM), containing triterpenes and polysaccharides extracted from medicinalmushroom Ganoderma lucidum, affects adipocyte differentiation and glucose uptake in 3T3-L1 cells.

Methods: 3T3-L1 pre-adipocytes were differentiated into adipocytes and treated with RM (0-300 μg/ml). Adipocytedifferentiation/lipid uptake was evaluated by oil red O staining and triglyceride and glycerol concentrations weredetermined. Gene expression was evaluated by semi-quantitative RT-PCR and Western blot analysis. Glucose uptakewas determined with [3H]-glucose.

Results: RM inhibited adipocyte differentiation through the suppresion of expression of adipogenic transcriptionfactors peroxisome proliferator-activated receptor-g (PPAR-g), sterol regulatory element binding element protein-1c(SREBP-1c) and CCAAT/enhancer binding protein-a (C/EBP-a). RM also suppressed expression of enzymes andproteins responsible for lipid synthesis, transport and storage: fatty acid synthase (FAS), acyl-CoA synthetase-1(ACS1), fatty acid binding protein-4 (FABP4), fatty acid transport protein-1 (FATP1) and perilipin. RM induced AMP-activated protein kinase (AMPK) and increased glucose uptake by adipocytes.

Conclusion: Our study suggests that RM can control adipocyte differentiation and glucose uptake. The healthbenefits of ReishiMax warrant further clinical studies.

BackgroundObesity is increasing at an alarming rate in the devel-oped as well as developing countries [1]. In the UnitedStates obesity is increasing not only in adults but also inchildren [2]. Among various factors which contribute tothe likelihood of death, obesity has escalated the chancesof death by 20% and it has lately surpassed smoking asthe number one cause of death in the US [3,4]. Accord-ing to survey carried out in 2007-2008 by the NationalHealth and Nutrition Examination Survey (NHANES)nearly 32.2% of adult men and 35.5% of adult womenwere obese [5]. There are numerous epidemiological

studies indicating that obese humans are at elevated riskof developing non-insulin-dependent (type 2) diabetesmellitus, hypertension, cancer and atherosclerosis [3,6,7].There are several lines of evidence to show that obe-

sity triggers the dysregulation of the endocrine functionof the adipose tissue [8,9]. This suggests that adiposetissue is no longer considered to be an inert tissue solelyresponsible for energy store, instead is recognized as amajor secretory organ, releasing a variety of adipocyto-kines such as adiponectin, leptin, resitin and visfatin[10]. These adipocytokines provide the link betweenobesity, insulin resistance and inflammatory disorders[10,11]. Differentiation of fibroblasts into adipose tissuerequires chronological changes in the expression ofnumerous genes [12-14]. The initial events are orche-strated by several transcription factors, CCAAT/

* Correspondence: [email protected] Research Laboratory, Methodist Research Institute, Indiana UniversityHealth, 1800 N Capitol Ave, E504, Indianapolis, IN 46202, USAFull list of author information is available at the end of the article

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

© 2011 Thyagarajan-Sahu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, andreproduction in any medium, provided the original work is properly cited.

Page 2: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

enhancer binding protein-a (C/EBP-a), sterol regulatoryelement binding protein-1c (SREBP-1c) and peroxisomeproliferators-activator receptor-g (PPAR-g). PPAR-g isinvolved in the regulation of genes controlling lipiduptake and is also a “master” regulator that triggers thecomplete process of adipogenesis [15]. These proteinsparticipate in a transcriptional cascade that controls theexpression of a number of genes which are essential inthe lipid accumulation in adipocytes during the processof differentiation [16,17]. Sterol regulatory element bind-ing proteins (SREBPs) are transcription factors that havebeen associated with lipogenesis regulating the expres-sion of acetyl-CoA carboxylase (ACC), fatty acidsynthase (FAS) and acyl-CoA synthase (ACS) [18]. Theexpression of the above factors alone cannot promotedifferentiation of pre-adipocytes, but when co-expressedwith on adipocytes expressing PPAR-g cell differentia-tion is enhanced [19-22]. Differentiated adipocytes alsosecrete cytokines tumor necrosis factor-a (TNF-a), andinterleukins (IL-6 and IL-1b) which are major regulatorsof adipocyte metabolism [23]. Hence, adipose tissueplays an important role in homeostasis of energy and isemerging as a major drug target for obesity and obesitymediated metabolic disorders [24-26]. Recent studieshave shown a strong link between obesity and type 2diabetes and insulin resistance [27]. Therefore, variouspharmacologic agents (e.g. thiazolidinediones and met-formin) are used to enhance insulin sensitivity [28]. Amain mode of action of a common type 2 diabetes drug,metformin is an activation of AMP-activated proteinkinase (AMPK) in skeletal muscles and hepatocytes [29].Medicinal mushroom Ganoderma lucidum, which is

well recognized by the Traditional Chinese Medicine(TCM) [30-33], is globally used as a popular dietary sup-plement. We have previously demonstrated that Reishi-Max (RM), a dietary supplement containing triterpenesand polysaccharides extracted from medicinal mush-room G. lucidum, is effective in inhibiting the prolifera-tion, invasive behavior and angiogenesis in differentcancer models [34-39]. In the present study we evalu-ated the effect of RM on the adipocyte differentiationand glucose uptake in adipocytes. Our data suggest thatRM can be used as a natural agent to control obesityand associated type 2 diabetes.

MethodsMaterials3T3-L1 preadipocytes, Dulbecco’s modified Eagle’s(DMEM) medium, Trypsin-EDTA were obtained fromAmerican Type Culture Collection (ATCC, Manassas,VA, USA). Fetal calf serum (FCS) was purchased fromColorado serum company (Denver, CO, USA). Fetalbovine serum (FBS), Penicillin and streptomycin wereobtained from Invitrogen (Carlsbad, CA, USA). Insulin

(INS), dexamethasone (DEX), isobutyl-methylxanthine(IBMX), oil red O, isopropanol and dimethyl sulphoxide(DMSO) were received from Sigma (St. Louis, MO,USA). Dulbecco’s Phosphate Buffered Saline (DPBS) wasobtained from Lonza (Walkerville, MD, USA). Reishi-Max (RM) was supplied by Pharmanex (Provo, UT). RMis a standardized Ganoderma lucidum extract containing6% triterpenes and 13.5% polysaccharides and theextraction procedure was previously described [40]. RMstock solution was prepared in DMSO.

Cell culture and adipocyte differentiation3T3-L1 preadipocytes were maintained in DMEM, sup-plemented with 10% FCS, penicillin (100 units/ml) andstreptomycin (100 μg/ml) at 37°C in humidified atmo-sphere with 5% CO2. Cell differentiation was initiated aspreviously described [41]. Briefly, cells were grown in 6well plates until 2 days post-confluence. Differentiationwas induced by adding 1 μg/ml of insulin, 0.25 μM ofdexamethasone and 0.5 mM isobutyl-methylxanthine inDMEM with 10% FBS. The INS-DEX-IBMX mediumwas replaced after 2 days to medium with insulin alonefor another 2 days after which they were supplementedwith 10% FBS every other day thereafter. To evaluatethe role of RM on lipid accumulation 3T3-L1 cells weretreated with 0-300 μg/ml of RM along with the differen-tiation medium containing INS-DEX-IBMX. The differ-entiated cells were used after 9 days of initiating thedifferentiation. All cells, including controls cells, weretreated with the same concentration of DMSO (0.3%).

Oil red O stainingThe lipids accumulated in the adipocytes were quanti-fied after staining the 3T3-L1 cells with oil red O stain-ing [42]. Briefly, after differentiation the cells were fixedwith 10% formalin for 1 hour and washed with 60% iso-propanol. After air drying the plates were stained withoil red O working solution (6 parts of 0.35% stock Oilred O and 4 parts of distilled water) for 30 min andrinsed with water. Images were obtained using an Olym-pus CX40 microscope (Center Valley, PA, USA) at 20×magnification, picture frame software from Optronics(Goleta, CA, USA) was used to obtain all images atsimilar intensities. To quantify the amount lipid uptake,the oil red O stain was eluted by adding 100% iso-pro-panol for 10 min, and the absorbance measured at 510nm on a microplate spectrophotometer using the Gen5software by BioTek Instruments (Winooski, VT, USA).

Analysis of triglycerides (TG)During differentiation 3T3-L1 cells were treated withRM (0-300 μg/ml). Subsequently the cells were rinsedwith PBS, scrapped and collected [43,44]. Triglycerides(TG) were quantified in the extract according to

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 2 of 14

Page 3: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

manufacture’s protocol (Triglyceride GPO-Trinder Kit,St. Louis, MO, USA).

Lipolysis determinationLipolysis was determined as the amount of free endo-genous glycerol released after RM treatment (0-300 μg/ml) into the conditioned medium. Glycerol concentra-tion was measured using the GPO-Trinder assay kit(Sigma, St Louis, MO, USA), according manufacture’sprotocol.

Isolation and analysis of RNATotal RNAs were isolated from 3T3-L1 adipocytes usingRNeasy Mini Kit (Qiagen, Valencia, CA) after the cellswere treated with RM (0-300 ug/ml) during the differen-tiation process. Each sample of first-strand cDNA wassynthesized from 2 μg total RNA using SuperScript IIIfirst-strand synthesis system (Invitrogen, Carlsbad, CA,USA) according to manufacturer’s protocol using DNAthermal cycler 480 (Perkin Elmer, Emeryville, CA, USA).The cDNA was amplified using Platinum PCR mastermix (Invitrogen, Carlsbad, CA) using the following for-ward and reverse primers: PPAR-g (NM_011146.2) for-ward primer 5’-TTT-TCA-AGG-GTG-CCA-GTT-TC-3’and reverse primer 5’-AAT-CCT-TGG-CCC-TCT-GAG-AT-3’ (PCR product 197 bp); SREBP-1c(NM_011480.2) forward primer 5’-TGT-TGG-CAT-CCT-GCT-ATC-TG-3’ and reverse primer 5’-AGG-GAA-AGC-TTT-GGG-GTC-TA-3’ (PCR product 189bp); C/EBP-a (NM_007678) forward primer 5’-TTA-CAA-CAG-GCC-AGG-TTT-CC-3’ and reverse primer5’-GGC-TGG-CGA-CAT-ACA-GTA-CA-3’ (PCR pro-duct 189 bp); FABP4 (NM_024406) forward primer 5’-TCA-CCT-GGA-AGA-CAG-CTC-CT-3’ and reverseprimer 5’-AAT-CCC-CAT-TTA-CGC-TGA-TG-3’ (PCRproduct 162 bp); FATP1 (NM_011977) forward primer5’-TGC-CTC-TGC-CTT-GAT-CTT-TT-3’ and reverseprimer 5’-GGA-ACC-GTG-GAT-GAA-CCT-AA-3’(PCR product 161 bp); FAS (NM_007988.3) forward pri-mer 5’-TTG-CTG-GCA-CTA-CAG-AAT-GC-3’ andreverse primer 5’-AAC-AGC-CTC-AGA-GCG-ACA-AT-3’ (PCR product 192 bp); ACS1 (NM_007981.3) for-ward primer 5’-CAA-CCC-AGA-ACC-ATG-GAA-GT-3’and reverse primer 5’-CTG-ACT-GCA-TGG-AGA-GGT-CA-3’ (PCR product 195 bp); perillipin(NM_175640.1) forward primer 5’-AAG-GAT-CCT-GCA-CCT-CAC-AC-3’ and reverse primer 5’-CCT-CTG-CTG-AAG-GGT-TAT-CG-3’ (PCR product 191bp); LPL (NM_008509.2) forward primer 5’-TCC-AAG-GAA-GCC-TTT-GAG-AA-3’ and reverse primer 5’-CCA-TCC-TCA-GTC-CCA-GAA-AA-3’ (PCR product186 bp); b-actin (NM_007393.2) forward primer 5’-AGC-CAT-GTA-CGT-AGC-CAT-CC-3’ and reverse 5’-TCC-CTC-TCA-GCT-GTG-GTG-GTG-AA-3’ (PCR

product 211 bp). PCR reactions were performed for 30cycles, unless otherwise indicated, to identify the linearrange for PCR. PCR products were separated on a 1.5%agarose gel and photographed. The PCR products werequantified using Flourchem software (Alpha Innotech,San Leandro, CA).

Glucose uptakeGlucose uptake was analyzed by measuring the uptakeof 2-deoxy-D-[3H] glucose as described previously[45,46]. Briefly, confluent 3T3-L1 adipocytes grown in12 well plates were rinsed twice with serum free no-glu-cose DMEM medium, and incubated with 2 ml of thesame medium in incubator with 8% CO2 at 37°C for 2hours. The cells were washed with Krebs-Ringer-Hepes(KRP) buffer and incubated in 0.9 ml of this buffer at37°C for 30 minutes. Insulin (0-200 nM) and RM (0-200μg/ml) were added in the last 20 minutes. Glucoseuptake was initiated by adding 0.1 ml of KRP buffer, 5μCi/ml of 2-deoxy-D-[3H]-glucose and 1 mM of deoxy-glucose (final concentration). After 10 min, the glucoseuptake was terminated by washing the cells thrice withcold PBS. The cells were lysed with 0.7 ml of 1% TritonX-100 at 37°C for 20 minutes, and the radioactive glu-cose uptake was determined by the scintillation counter(Beckman Inst. Inc, Fullerton, CA, USA).

Western Blot analysis3T3-L1 pre-adipocytes were treated with RM (0-300 μg/ml) during the process of differentiation as indicated inthe text (perilipin analysis) and whole cell extracts pre-pared as previously described [47]. Alternatively, differ-entiated adipocytes were incubated in serum free mediafor 2 hours and subsequently stimulated with RM (0-100 μg/ml) or Insulin (0-200 nM) for 30 minutes(AMPK analysis). Equal amounts of cellular proteins (30μg/lane) were separated on NuPAGE 12% or 4-12% Bis-Tris gel (Invitrogen, Carlsbad, CA, USA), and trans-ferred to a PVDF membrane (Millipore, Bedford, MA,USA) using XCell II blot module (Invitrogen). The pro-tein expression was detected with the correspondingprimary antibodies for anti-perilipin, anti-phospho-AMPKa (Thr-172), anti-AMPK (Cell Signaling, Beverly,MA, USA) and anti-b-actin antibody (Santa Cruz Bio-technology, Santa Cruz, CA, USA). Protein expressionwas visualized using the ECL Western Blotting Detec-tion System (Santa Cruz Biotechnology). Densitometricanalysis of the bands for the expression of protein wasdone with Flourchem software (Alpha Innotech, SanLeandro, CA).

Statistical AnalysisData are represented as mean ± S.D and were analyzedusing SigmaPlot 11.2 (Systat Software Inc, San Jose, CA,

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 3 of 14

Page 4: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

USA). The differences between the groups were ana-lyzed by one way ANOVA with Bonferroni multiplecomparison post-hoc test.

ResultsEffect of RM on lipid accumulation, triglyceride uptakeand glycerol accumulationTo evaluate whether RM affects the lipid uptake in adi-pocytes, we analyzed the changes in the amount of tri-glycerides and glycerol after inducing adipocytedifferentiation. Adipocytes accumulate lipids by twomajor mechanisms either by de novo lipogenesis fromnon-lipid precursors or by uptake of fatty acids from theplasma [48]. To evaluate the effect of RM on lipiduptake by adipocytes, cells were treated with RM (0-300μg/ml) in the presence of the differentiation mix of 1μg/ml of INS, 0.25 μM of DEX and 0.5 mM IBMX inDMEM with 10% FBS as described in Materials andMethods. As seen in Figure 1A, differentiation of preadi-pocytes (a) to adipocytes (b) was associated with theincreased oil red O positive cells, whereas RM treatmentmarkedly suppressed lipid accumulation in differentiatedadipocytes (Figure 1A b-e, Figure 1B). Since mostreserves of energy in the human body are stored in adi-pocytes in the form of triacylglycerol (TAG) [12], weassessed the amount of triglycerides (TG) and glycerolreleased due to lipolysis from adipocytes treated withRM. As expected, TG and glycerol levels in adipocyteswere significantly decreased in a dose response mannerafter RM treatment (Figure 1C and Figure 1D).

RM inhibits the expression of transcription factorscontrolling lipogenic pathwaysNext we examined the role of transcription factorsinvolved in adipocyte differentiation. The effect of RMon the expression of PPAR-g, SREBP-1c and C/EBP-awas evaluated by RT-PCR. As seen in Figure 2, differ-entiated adipocytes had substantially increased levels ofthe PPAR-g, SREBP-1c and C/EBP-a compared to pre-adipocytes. Moreover, treatment of pre-adipocytes withReishiMax (0-300 ug/ml) decreased the expression ofPPAR-g (Figure 2A), SREBP-1c (Figure 2B) and C/EBP-a (Figure 2C) in a dose dependent manner, sug-gesting that the RM inhibits adipocyte lipogenesisthrough PPAR-g, SREBP-1c and C/EBP-a regulatedgenes.

RM suppresses expression of proteins regulatingsynthesis and transport of fatty acidsAs shown above, RM treatment inhibits the expressionof PPAR-g, SREBP-1c and C/EBP-a which regulategenes responsible for the synthesis and transport of fattyacids. Thus, we determined whether RM also suppressesexpression of the fatty acid synthesis enzymes (FAS and

ACS1) and proteins involved in the transport of fattyacids (FABP4 and FATP1). 3T3-L1 cells were differen-tiated and treated with RM (0-300 ug/ml) and expres-sion of FAS, ACS1, FABP4 and FATP1 evaluated byRT-PCR as described in Materials and Methods. Asseen in Figure 3A and 3B, RM treatment significantlyinhibited the expression of FAS and ACS1 in a dose-response manner. In addition, RM treatment signifi-cantly inhibited the expression of FABP4 (Figure 4A),and FATP1 (Figure 4B), Therefore our data suggest thatRM suppresses expression of proteins involved in lipidsynthesis and lipid transport.

Effect of RM on the expression of perilipin and LPLDuring the process of differentiation the adipocytesaccumulated lipid in the form of lipid droplets. Theselipid droplets are protected by different fat specific pro-teins including perilipin. Since RM treatment decreasesthe expression of the transcription factors, enzymes andtransporter proteins involved in the synthesis and trans-port of fatty acids, we were interested to further deter-mine whether RM treatment could also modulate theexpression of perilipin. As seen in Figure 5, differentia-tion from preadipocytes to adipocytes markedlyincreased the levels of perilipin, whereas RM suppresseddose-dependently its expression at mRNA (Figure 5A)as well as protein (Figure 5B) levels, respectively. Lipiddroplets are hydrolyzed by lipoprotein lipase (LPL) [49]which expression is controlled by SREBP-1c during adi-pocyte differentiation [50]. Since RM inhibits productionof glycerol and SREBP-1c (Figure 1D, 2B), we evaluatedthe effect of RM (0-300 ug/ml) on LPL expression byRT-PCR during the adipocyte differentiation. However,RM did not show any effect on LPL expression (notshown).

RM induces AMPK and glucose uptake in adipocytesThe activation/phosphorylation of AMPK is crucial forthe treatment of diabetes and metabolic syndrome [51].To evaluate whether RM activates AMPK, 3T3-L1 adi-pocytes were treated with RM (0, 50, 100 μg/ml) orinsulin (100, 200 nM) for 30 minutes and phosphoryla-tion of AMPK determined by Western blot analysis withanti-pAMPK-Thr172 antibody. As seen in Figure 6A,RM induced phosphorylation of AMPK in a doseresponse manner and this effect was comparable to theinsulin treatment. Because AMPK can function as anenergy sensor and also stimulates glucose uptake[52,53], we evaluated whether RM stimulates glucoseuptake in differentiated adipocytes. As expected, RMmarkedly induced glucose uptake in adipocytes in adose response manner (Figure 6B), confirming that RM-induced phosphorylation of AMPK results in the glucoseuptake.

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 4 of 14

Page 5: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

Figure 1 Effect of RM on lipid accumulation during differentiation. 3T3-L1 pre-adipocytes 2 days after confluence were induced todifferentiate in the presence of RM (0-300 μg/ml). At day 9 adipocytes were stained with Oil red O as shown in Figure 1A. (a) pre-adipocytes, (b)adipocytes [RM-0], (c) adipocytes [RM-100 μg/ml], (d) adipocytes [RM-200 μg/ml], (e) adipocytes [RM-300 μg/ml]. (B) Quantification of lipids wasmeasured after eluting with isopropanol and reading the absorbance at 510 nm. (C) triglyceride and (D) glycerol concentration was determinedas described in Materials and Methods. Each experiment was performed three times in triplicates. Results are depicted as mean ± SD, statisticalsignificance was calculated (letters that differ indicate, p ≤ 0.05). For our studies we used cells up to passage twelve.

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 5 of 14

Page 6: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

Figure 2 Effect of RM on adipogenic transcription factors. 3T3-L1 pre-adipocytes 2 days after confluence were induced to differentiate in thepresence of RM (0-300 μg/ml). At day 9 adipocytes RNA was isolated and RT-PCR for mRNA expression of (A) PPAR-g, (B) SREBP-1 and (C) c/EBP-a was performed as described in Materials and Methods. Ratio is calculated against b-actin represented as arbitary units of integrated densityvalue (IDV). Each experiment was repeated twice in duplicate and results are depicted as mean ± SD, statistical significance was calculated(letters that differ indicate, p ≤ 0.05).

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 6 of 14

Page 7: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

Figure 3 Effect of RM on FAS and ACS1. 3T3-L1 pre-adipocytes 2 days after confluence were induced to differentiate in the presence of RM(0-300 μg/ml). At day 9 adipocytes RNA was isolated and RT-PCR for mRNA expression of (A) fatty acid synthase (FAS) and (B) acyl-coAsynthetase (ACS1) was performed. Ratio is calculated against b-actin represented as arbitary units of integrated density value (IDV). Eachexperiment was repeated twice in duplicate and results are depicted as mean ± SD, statistical significance was calculated (letters that differindicate, p ≤ 0.05).

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 7 of 14

Page 8: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

Figure 4 Effect of RM on FABP4 and FATP1. 3T3-L1 pre-adipocytes 2 days after confluence were induced to differentiate in the presence of RM(0-300 μg/ml). At day 9 adipocytes RNA was isolated and RT-PCR for mRNA expression of (A) fatty acid binding protein 4 (FABP4) and (B) fatty acidtransport protein 1 (FATP1) was performed. Ratio is calculated against b-actin represented as arbitary units of integrated density value (IDV). Eachexperiment was repeated twice in duplicate and results are depicted as mean ± SD, statistical significance was calculated (letters that differindicate, p ≤ 0.05).

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 8 of 14

Page 9: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

Figure 5 Effect of RM on mRNA levels of perilipin and protein expression for perilipin. 3T3-L1 pre-adipocytes 2 days after confluence wereinduced to differentiate in the presence of RM (0-300 μg/ml). At day 9 adipocytes RNA and proteins were isolated. (A) mRNA levels of perilipin weredetermined by RT-PCR and (B) protein expression of perilipin was determined by Western blot analysis. Each experiment was repeated thrice and resultsare depicted as mean ± SD, statistical significance was calculated (letters that differ indicate, p ≤ 0.05).

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 9 of 14

Page 10: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

Figure 6 Effect of RM on AMPK and glucose uptake. 3T3-L1 pre-adipocytes 2 days after confluence were induced to differentiate. (A) 3T3-L1adipocytes were treated with RM (0, 50, 100 μg/ml) or insulin (100, 200 nM) for 30 minutes and the expression of phopho-AMPK was detectedby Western blot analysis as described in Materials and Methods. Immunoblots are representative of 3 independent experiments. Data representsmean ± SD. *p < 0.05 vs adipocyte control cells. (B) Glucose uptake was determined in 3T3-L1 adipocytes treated with RM (0, 50, 100 μg/ml) orinsulin (200 nM) as described in Materials and Methods. The results are mean ± SD (n = 12), *p < 0.05 vs adipocyte control cells.

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 10 of 14

Page 11: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

DiscussionObesity is increasing at an alarming rate in both thegenders of all age groups around the world includingUnited States [54]. According to the National Bureau ofEconomic Research report, the prevalence of obesitywill rise to 40% in men and 43% in women by 2020[55]. The major factors contributing to obesity aresedentary life style, inactivity, over eating and distur-bances in the metabolism of fatty acids [56]. Variousstudies indicated that obese humans are at increasedrisk of developing diabetes, hypertension, cancer andatherosclerosis [57-59]. Thus, adipose tissue is recog-nized as a major secretory organ, releasing a variety ofadipocytokines (e.g. adiponectin, leptin, resitin andothers) which provide the link between obesity, insulinresistance and inflammatory disorders [60]. Therefore,new therapeutic agents that can regulate adipogenesisand glucose uptake can be employed to control obesityand type 2 diabetes.In the present study, we evaluated the effect of Reishi-

Max (RM), dietary supplement containing triterpenesand polysaccharides isolated from medicinal mushroomGanoderma lucidum, on adipocyte differentiation andglucose uptake in adipocytes. Here, we show that RMinhibited adipocyte differentiation/lipid accumulationthrough: a) the down-regulation of expression of tran-scription factors PPAR-g, SREBP-1c and C/EBP-a, andb) the suppression of expression of genes responsible forlipid synthesis (FAS, ACS1), lipid transport (FABP4,FATP1) and lipid storage (perillipin). However, we didnot observe any changes in the expression of LPL,

which expression is also controlled by PPAR-g, SREBP-1c and C/EBP-a. In agreement with our study, hydroxy-torosol from olive oil inhibited lipid accumulation dur-ing adipocyte differentiation and inhibited all testedgenes except LPL [61]. Nevertheless, others demon-strated down-regulation of LPL expression associatedwith the adipocyte differentiation [62,63]. These contra-dictory results might be explained by the use of differentcell models: mouse 3T3-L1 (our study and [63]), C3H10T1/2 [61] or human pre-adipocytes [62] or activation ofb-catenin pathway [63]. Finally, RM activated AMPKresulting in the increased glucose uptake by adipocytes(Figure 7).On the molecular level, C/EBP-a, PPAR-g and SREBP-

1c are induced during adipocyte differentiation [12].Specifically, PPAR-g and SREBP-1c mRNAs start to beexpressed at the very early/early stage (day 1-2 post-confluence) followed by the expression of C/EBP-a atthe intermediate stage (day 4 post-confluence) [50].These transcription factors further controls expressionof adipocyte-specific genes (e.g. FAS, ACS1, FABP4,FATP1 and perilipin) at the late stage (day 5 post-con-fluence) leading to the fat droplet formation [64]. There-fore, the inhibition of PPAR-g, SREBP-1c and C/EBP-a,by RM at the early/intermediate stages results in thesuppression of expression of adipocyte specific genesand lipid formation at the late stage of adipocytedifferentiation.The inhibition of adipogenesis by RM is in an agree-

ment with recent studies demonstrating anti-adipogeniceffects of white tea or bitter melon extracts or other

AMPK Glucose uptake

SREBP-1c PPAR- & C/EBP- PPAR- & C/EBP-

ACS1 & FAS FATP1 & FABP4 & perilipin FAS

Lipidsynthesis

Lipidsynthesis

Lipidtransport

Lipidstorage

RM

Figure 7 Schematic of RM activity.

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 11 of 14

Page 12: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

isolated phytochemicals [65-69]. Moreover, activation ofAMPK was previously associated with the inhibition ofadipocyte differentiation [70] or increased glucoseuptake. Indeed, our data are in an agreement withrecent reports by Ha et al [71,72] demonstrating anincrease of glucose uptake and inhibition of adipocytedifferentiation through the activation of AMPK in 3T3-L1 cells.During the preparation of the present manuscript, Lee

et al. demonstrated that some purified triterpenes fromG. lucidum inhibit adipocyte differentiation, decreaselipid accumulation and down-regulate expression ofPPAR-g, SREBP-1c, C/EBP-a, FAS and ACC [73-75].Although the identification of biologically active compo-nents from G. lucidum is important for their possibletherapeutic use, and more than 130 triterpenes havebeen isolated and new triterpenes continue to be identi-fied [76], the yield of a majority of purified triterpenes isgenerally low. Therefore, the possible therapeutic use ofpurified triterpenes is currently limited. On the otherhand, in our study we used standardized dietary supple-ment ReishiMax (RM) containing 6% triterpenes and13.5% polysaccharides. Moreover, we have previouslyidentified some of the triterpenes in RM (e.g. ganodericacids A, F, H, Mh, S, lucidenic acid B, D, D1, E1, L andmethyl lucidenate G) [77], that can be used for the stan-dardization of the active supplements or G. lucidumextracts. Our study is with agreement with previousstudy demonstrating stimulation of glucose uptake andactivation of AMPK in rat muscle cells [78]. However,the authors used uncharacterized extract prepared fromG. lucidum purchased from the Korean market [78]. Onthe other hand G. lucidum extract (GE), containingapproximately 10% of ganoderic acid A, induced adipo-cyte differentiation and expression PPAR-g [79].Although GE activated PPAR-g, ganoderic acid A itselfdid not show any effect on PPAR-g, suggesting thatother compounds in GE are responsible for the GEactivity [79]. Finally, standardized G. lucidum extract,containing polysaccharides, adenosine and ganodericacid A, demonstrated mild anti-diabetic effects in a con-trolled human trial [80]. Since the presence and theamount of specific biologically active compounds in G.lucidum extracts depends on the source of G. lucidum,cultivation conditions, storage and extraction process[81], it is not surprising that extracts from the samemushroom could have different or opposite activities.In summary, only standardized and characterized diet-

ary supplements/extracts should be considered for theuse in alternative medicine. Since the use of dietary sup-plements is not regulated and they are freely accessible,the proper characterization must be performed andassociated with the specific activity.

ConclusionsIn conclusion, the results of our study show that chemi-cally characterized dietary supplement ReishiMax [RM],containing triterpenes and polysaccharides isolated frommedicinal mushroom Ganoderma lucidum, inhibits theexpression of key transcription factors and genesresponsible for adipocyte differentiation, synthesis, trans-port and storage of lipids. In addition, RM activatesAMPK and stimulates glucose uptake to the levels com-parable to the insulin activity. Further preclinical studiesevaluating RM activity in the management of obesityand type 2 diabetes are warranted.

List of abbreviationsACS1: acyl-CoA synthetase-1; AMPK: AMP-activated protein kinase; C/EBP-α:CCAAT/enhancer binding protein-α; FABP4: fatty acid binding protein-4; FAS:fatty acid synthase; FATP1: fatty acid transport protein-1; LPL: lipoproteinlipase; PPAR-γ: peroxisome proliferator-activated receptor-γ; RM: ReishiMax;SREBP-1c: sterol regulatory element binding element protein-1c.

AcknowledgementsThis study was supported by the Methodist Research Institute, IndianaUniversity Health, Indianapolis and a grant from The Catherine PeacheyFund, Indianapolis, Indiana, USA to A. T-S.

Author details1Cancer Research Laboratory, Methodist Research Institute, Indiana UniversityHealth, 1800 N Capitol Ave, E504, Indianapolis, IN 46202, USA. 2Departmentof Medicine, School of Medicine, Indiana University, Indianapolis, IN, USA.3Indiana University Simon Cancer Center, Indianapolis, IN, 46202, USA.

Authors’ contributionsDS designed research; AT-S and BL conducted research; AT-S, BL and DSanalyzed data; AT-S and DS wrote the paper; DS had the primaryresponsibility for final content. All authors read and approved the finalmanuscript.

Competing interestsThe authors declare that they have no competing interests.

Received: 5 August 2011 Accepted: 19 September 2011Published: 19 September 2011

References1. Smith PD, O’Halloran P, Hahn DL, Grasmick M, Radant L: Screening for

obesity: clinical tools in evolution, a WREN study. Wisconsin MedicalJournal 2010, 109(5):274-278.

2. Pi-Sunyer X: The medical risks of obesity. Postgrad Med 2009, 121(6):21-33.3. Shi Y, Burn P: Lipid metabolic enzymes: emerging drug targets for the

treatment of obesity. Nat Rev Drug Discov 2004, 3(8):695-710.4. McHugh MD: Fit or fat? A review of the debate on deaths attributable to

obesity. Public Health Nurs 2006, 23(3):264-270.5. Flegal KM, Carroll MD, Ogden CL, Curtin LR: Prevalence and trends in

obesity among US adults, 1999-2008. JAMA 303(3):235-241.6. Wellen KE, Hotamisligil GS: Inflammation, stress, and diabetes. J Clin Invest

2005, 115(5):1111-1119.7. Berg AH, Scherer PE: Adipose tissue, inflammation, and cardiovascular

disease. Circ Res 2005, 96(9):939-949.8. Gimeno RE, Klaman LD: Adipose tissue as an active endocrine organ:

recent advances. Curr Opin Pharmacol 2005, 5(2):122-128.9. Frayn KN: Obesity and metabolic disease: is adipose tissue the culprit?

Proc Nutr Soc 2005, 64(1):7-13.10. Tilg H, Moschen AR: Adipocytokines: mediators linking adipose tissue,

inflammation and immunity. Nat Rev Immunol 2006, 6(10):772-783.

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 12 of 14

Page 13: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

11. Schaffler A, Scholmerich J, Salzberger B: Adipose tissue as animmunological organ: Toll-like receptors, C1q/TNFs and CTRPs. TrendsImmunol 2007, 28(9):393-399.

12. Gregoire FM, Smas CM, Sul HS: Understanding adipocyte differentiation.Physiol Rev 1998, 78(3):783-809.

13. MacDougald OA, Lane MD: Transcriptional regulation of gene expressionduring adipocyte differentiation. Annu Rev Biochem 1995, 64:345-373.

14. Rosen ED, Walkey CJ, Puigserver P, Spiegelman BM: Transcriptionalregulation of adipogenesis. Genes Dev 2000, 14(11):1293-1307.

15. Spiegelman BM, Flier JS: Adipogenesis and obesity: rounding out the bigpicture. Cell 1996, 87(3):377-389.

16. Rangwala SM, Lazar MA: Transcriptional control of adipogenesis. Annu RevNutr 2000, 20:535-559.

17. Rosen ED, Spiegelman BM: Molecular regulation of adipogenesis. AnnuRev Cell Dev Biol 2000, 16:145-171.

18. Kolehmainen M, Vidal H, Alhava E, Uusitupa MI: Sterol regulatory elementbinding protein 1c (SREBP-1c) expression in human obesity. Obes Res2001, 9(11):706-712.

19. Farmer SR: Regulation of PPARgamma activity during adipogenesis. Int JObes (Lond) 2005, 29(Suppl 1):S13-16.

20. Tontonoz P, Hu E, Graves RA, Budavari AI, Spiegelman BM: mPPAR gamma2: tissue-specific regulator of an adipocyte enhancer. Genes Dev 1994,8(10):1224-1234.

21. Rosen ED, Sarraf P, Troy AE, Bradwin G, Moore K, Milstone DS,Spiegelman BM, Mortensen RM: PPAR gamma is required for thedifferentiation of adipose tissue in vivo and in vitro. Mol Cell 1999,4(4):611-617.

22. Wu Z, Rosen ED, Brun R, Hauser S, Adelmant G, Troy AE, McKeon C,Darlington GJ, Spiegelman BM: Cross-regulation of C/EBP alpha and PPARgamma controls the transcriptional pathway of adipogenesis and insulinsensitivity. Mol Cell 1999, 3(2):151-158.

23. Coppack SW: Pro-inflammatory cytokines and adipose tissue. Proc NutrSoc 2001, 60(3):349-356.

24. Nawrocki AR, Scherer PE: Keynote review: the adipocyte as a drugdiscovery target. Drug Discov Today 2005, 10(18):1219-1230.

25. Wasan KM, Looije NA: Emerging pharmacological approaches to thetreatment of obesity. J Pharm Pharm Sci 2005, 8(2):259-271.

26. Curtis R, Geesaman BJ, DiStefano PS: Ageing and metabolism: drugdiscovery opportunities. Nat Rev Drug Discov 2005, 4(7):569-580.

27. Kahn SE, Hull RL, Utzschneider KM: Mechanisms linking obesity to insulinresistance and type 2 diabetes. Nature 2006, 444(7121):840-846.

28. Moller DE: New drug targets for type 2 diabetes and the metabolicsyndrome. Nature 2001, 414(6865):821-827.

29. Zhou G, Myers R, Li Y, Chen Y, Shen X, Fenyk-Melody J, Wu M, Ventre J,Doebber T, Fujii N, et al: Role of AMP-activated protein kinase inmechanism of metformin action. J Clin Invest 2001, 108(8):1167-1174.

30. Sliva D: Ganoderma lucidum (Reishi) in cancer treatment. Integr CancerTher 2003, 2(4):358-364.

31. Sliva D: Cellular and physiological effects of Ganoderma lucidum (Reishi).Mini Rev Med Chem 2004, 4(8):873-879.

32. Sliva D: Ganoderma lucidum in cancer research. Leuk Res 2006,30(7):767-768.

33. Wasser S: Reishi (Ganoderma lucidum). Encyclopedia of Dietary Supplements2005, 603-622.

34. Thyagarajan A, Jiang J, Hopf A, Adamec J, Sliva D: Inhibition of oxidativestress-induced invasiveness of cancer cells by Ganoderma lucidum ismediated through the suppression of interleukin-8 secretion. Int J MolMed 2006, 18(4):657-664.

35. Thyagarajan A, Zhu J, Sliva D: Combined effect of green tea andGanoderma lucidum on invasive behavior of breast cancer cells. Int JOncol 2007, 30(4):963-969.

36. Jiang J, Slivova V, Sliva D: Ganoderma lucidum inhibits proliferation ofhuman breast cancer cells by down-regulation of estrogen receptor andNF-kappaB signaling. Int J Oncol 2006, 29(3):695-703.

37. Jiang J, Slivova V, Harvey K, Valachovicova T, Sliva D: Ganoderma lucidumsuppresses growth of breast cancer cells through the inhibition of Akt/NF-kappaB signaling. Nutr Cancer 2004, 49(2):209-216.

38. Jiang J, Slivova V, Valachovicova T, Harvey K, Sliva D: Ganoderma luciduminhibits proliferation and induces apoptosis in human prostate cancercells PC-3. Int J Oncol 2004, 24(5):1093-1099.

39. Stanley G, Harvey K, Slivova V, Jiang J, Sliva D: Ganoderma lucidumsuppresses angiogenesis through the inhibition of secretion of VEGFand TGF-beta1 from prostate cancer cells. Biochem Biophys Res Commun2005, 330(1):46-52.

40. Dudhgaonkar S, Thyagarajan A, Sliva D: Suppression of the inflammatoryresponse by triterpenes isolated from the mushroom Ganodermalucidum. Int Immunopharmacol 2009, 9(11):1272-1280.

41. Liu F, Kim J, Li Y, Liu X, Li J, Chen X: An extract of Lagerstroemia speciosaL. has insulin-like glucose uptake-stimulatory and adipocytedifferentiation-inhibitory activities in 3T3-L1 cells. J Nutr 2001,131(9):2242-2247.

42. Giri S, Rattan R, Haq E, Khan M, Yasmin R, Won JS, Key L, Singh AK, Singh I:AICAR inhibits adipocyte differentiation in 3T3L1 and restores metabolicalterations in diet-induced obesity mice model. Nutr Metab (Lond) 2006,3:31.

43. Shimabukuro M, Koyama K, Chen G, Wang MY, Trieu F, Lee Y, Newgard CB,Unger RH: Direct antidiabetic effect of leptin through triglyceridedepletion of tissues. Proc Natl Acad Sci USA 1997, 94(9):4637-4641.

44. Chakrabarti P, Kandror KV: FoxO1 controls insulin-dependent adiposetriglyceride lipase (ATGL) expression and lipolysis in adipocytes. J BiolChem 2009, 284(20):13296-13300.

45. Sakoda H, Ogihara T, Anai M, Funaki M, Inukai K, Katagiri H, Fukushima Y,Onishi Y, Ono H, Yazaki Y, et al: No correlation of plasma cell 1overexpression with insulin resistance in diabetic rats and 3T3-L1adipocytes. Diabetes 1999, 48(7):1365-1371.

46. Garcia de Herreros A, Birnbaum MJ: The acquisition of increased insulin-responsive hexose transport in 3T3-L1 adipocytes correlates withexpression of a novel transporter gene. J Biol Chem 1989,264(33):19994-19999.

47. Thyagarajan A, Jedinak A, Nguyen H, Terry C, Baldridge LA, Jiang J, Sliva D:Triterpenes From Ganoderma Lucidum Induce Autophagy in ColonCancer Through the Inhibition of p38 Mitogen-Activated Kinase (p38MAPK). Nutr Cancer 2010, 62(5):630-640.

48. Lafontan M: Advances in adipose tissue metabolism. Int J Obes (Lond)2008, 32(Suppl 7):S39-51.

49. Auwerx J, Leroy P, Schoonjans K: Lipoprotein lipase: recent contributionsfrom molecular biology. Crit Rev Clin Lab Sci 1992, 29(3-4):243-268.

50. Kim JB, Spiegelman BM: ADD1/SREBP1 promotes adipocyte differentiationand gene expression linked to fatty acid metabolism. Genes Dev 1996,10(9):1096-1107.

51. Zhang BB, Zhou G, Li C: AMPK: an emerging drug target for diabetes andthe metabolic syndrome. Cell Metab 2009, 9(5):407-416.

52. Carling D: The AMP-activated protein kinase cascade–a unifying systemfor energy control. Trends Biochem Sci 2004, 29(1):18-24.

53. Hardie DG: AMP-activated protein kinase as a drug target. Annu RevPharmacol Toxicol 2007, 47:185-210.

54. CDC: Obesity Trends Among U.S. Adults Between 1985 and 2009. 2009[http://www.cdc.gov/obesity/data/trends.html].

55. Research NBoE: The Increasing Prevalence of Obesity 2011 [http://www.nber.org/digest/jul08/w13181.html].

56. Mokdad AH, Serdula MK, Dietz WH, Bowman BA, Marks JS, Koplan JP: Thespread of the obesity epidemic in the United States, 1991-1998. JAMA1999, 282(16):1519-1522.

57. Okosun IS, Chandra KM, Choi S, Christman J, Dever GE, Prewitt TE:Hypertension and type 2 diabetes comorbidity in adults in the UnitedStates: risk of overall and regional adiposity. Obes Res 2001, 9(1):1-9.

58. Calle EE, Kaaks R: Overweight, obesity and cancer: epidemiologicalevidence and proposed mechanisms. Nat Rev Cancer 2004, 4(8):579-591.

59. Rajala MW, Scherer PE: Minireview: The adipocyte–at the crossroads ofenergy homeostasis, inflammation, and atherosclerosis. Endocrinology2003, 144(9):3765-3773.

60. Fantuzzi G: Adipose tissue, adipokines, and inflammation. J Allergy ClinImmunol 2005, 115(5):911-919, quiz 920.

61. Warnke I, Goralczyk R, Fuhrer E, Schwager J: Dietary constituents reducelipid accumulation in murine C3H10 T1/2 adipocytes: A novelfluorescent method to quantify fat droplets. Nutr Metab (Lond) 2011,8(1):30.

62. Díaz-Delfín J, del Mar Gutiérrez M, Gallego-Escuredo JM, Domingo JC,Gracia MMateo, Villarroya F, Domingo P, Giralt M: Effects of nevirapine andefavirenz on human adipocyte differentiation, gene expression, andrelease of adipokines and cytokines. Antiviral Res 2011, 91(2):112-9.

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 13 of 14

Page 14: RESEARCH ARTICLE Open Access ReishiMax, mushroom based

63. Lee H, Kang R, Bae S, Yoon Y: AICAR, an activator of AMPK, inhibitsadipogenesis via the WNT/β-catenin pathway in 3T3-L1 adipocytes. Int JMol Med 2011, 28(1):65-71.

64. Ntambi JM, Young-Cheul K: Adipocyte differentiation and geneexpression. J Nutr 2000, 130(12):3122S-3126S.

65. Hwang JT, Park IJ, Shin JI, Lee YK, Lee SK, Baik HW, Ha J, Park OJ: Genistein,EGCG, and capsaicin inhibit adipocyte differentiation process viaactivating AMP-activated protein kinase. Biochem Biophys Res Commun2005, 338(2):694-699.

66. Sohle J, Knott A, Holtzmann U, Siegner R, Gronniger E, Schepky A,Gallinat S, Wenck H, Stab F, Winnefeld M: White Tea extract induceslipolytic activity and inhibits adipogenesis in human subcutaneous (pre)-adipocytes. Nutr Metab (Lond) 2009, 6:20.

67. Nerurkar PV, Lee YK, Nerurkar VR: Momordica charantia (bitter melon)inhibits primary human adipocyte differentiation by modulatingadipogenic genes. BMC Complement Altern Med 2010, 10:34.

68. Lee H, Kang R, Yoon Y: Shikonin inhibits fat accumulation in 3T3-L1adipocytes. Phytother Res 2010, 24(3):344-351.

69. Olholm J, Paulsen SK, Cullberg KB, Richelsen B, Pedersen SB: Anti-inflammatory effect of resveratrol on adipokine expression andsecretion in human adipose tissue explants. Int J Obes (Lond) 2010,34(10):1546-1553.

70. Habinowski SA, Witters LA: The effects of AICAR on adipocytedifferentiation of 3T3-L1 cells. Biochem Biophys Res Commun 2001,286(5):852-856.

71. Ha do T, Trung TN, Phuong TT, Yim N, Chen QC, Bae K: The selectedflavonol glycoside derived from Sophorae Flos improves glucose uptakeand inhibits adipocyte differentiation via activation AMPK in 3T3-L1cells. Bioorg Med Chem Lett 2010, 20(20):6076-6081.

72. Ha do T, Nam Trung T, Bich Thu N, Van On T, Hai Nam N, Van Men C, ThiPhuong T, Bae K: Adlay seed extract (Coix lachryma-jobi L.) decreasedadipocyte differentiation and increased glucose uptake in 3T3-L1 cells. JMed Food 2010, 13(6):1331-1339.

73. Lee I, Seo J, Kim J, Kim H, Youn U, Lee J, Jung H, Na M, Hattori M, Min B,et al: Lanostane triterpenes from the fruiting bodies of Ganodermalucidum and their inhibitory effects on adipocyte differentiation in 3T3-L1 Cells. J Nat Prod 2010, 73(2):172-176.

74. Lee I, Kim H, Youn U, Kim J, Min B, Jung H, Na M, Hattori M, Bae K: Effectof lanostane triterpenes from the fruiting bodies of Ganoderma lucidumon adipocyte differentiation in 3T3-L1 cells. Planta Med 2010,76(14):1558-1563.

75. Lee I, Kim J, Ryoo I, Kim Y, Choo S, Yoo I, Min B, Na M, Hattori M, Bae K:Lanostane triterpenes from Ganoderma lucidum suppress theadipogenesis in 3T3-L1 cells through down-regulation of SREBP-1c.Bioorg Med Chem Lett 2010, 20(18):5577-5581.

76. Sliva D: Medicinal potential of Ganoderma lucidum. In Applied Mycology.Edited by: Rai M. Bridge, PD: CAB International; 2009:173-196.

77. Adamec J, Jannasch A, Dudhgaonkar S, Jedinak A, Sedlak M, Sliva D:Development of a new method for improved identification and relativequantification of unknown metabolites in complex samples:determination of a triterpenoid metabolic fingerprint for the in situcharacterization of Ganoderma bioactive compounds. J Sep Sci 2009,32(23-24):4052-4058.

78. Jung KH, Ha E, Kim MJ, Uhm YK, Kim HK, Hong SJ, Chung JH, Yim SV:Ganoderma lucidum extract stimulates glucose uptake in L6 rat skeletalmuscle cells. Acta Biochim Pol 2006, 53(3):597-601.

79. Shimojo Y, Kosaka K, Shirasawa T: Effect of Ganoderma lucidum extract onadipocyte differentiation and adiponectin gene expression in themurine pre-adipocyte cell line, 3T3-L1. Phytother Res 2010, 25(2):202-207.

80. Chu TT, Benzie IF, Lam CW, Fok BS, Lee KK, Tomlinson B: Study of potentialcardioprotective effects of Ganoderma lucidum (Lingzhi): results of acontrolled human intervention trial. Br J Nutr 2011, 1-11.

81. Sliva D, Sedlak M, Slivova V, Valachovicova T, Lloyd FP, Ho NW: Biologicactivity of spores and dried powder from Ganoderma lucidum for theinhibition of highly invasive human breast and prostate cancer cells. JAltern Complement Med 2003, 9(4):491-497.

Pre-publication historyThe pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6882/11/74/prepub

doi:10.1186/1472-6882-11-74Cite this article as: Thyagarajan-Sahu et al.: ReishiMax, mushroom baseddietary supplement, inhibits adipocyte differentiation, stimulatesglucose uptake and activates AMPK. BMC Complementary and AlternativeMedicine 2011 11:74.

Submit your next manuscript to BioMed Centraland take full advantage of:

• Convenient online submission

• Thorough peer review

• No space constraints or color figure charges

• Immediate publication on acceptance

• Inclusion in PubMed, CAS, Scopus and Google Scholar

• Research which is freely available for redistribution

Submit your manuscript at www.biomedcentral.com/submit

Thyagarajan-Sahu et al. BMC Complementary and Alternative Medicine 2011, 11:74http://www.biomedcentral.com/1472-6882/11/74

Page 14 of 14